Rotary engine.



PATENTBD 00T. 9, 1906.

T. GRosToN.

ROTARY ENGINE. APPLICATION FILED UGT. 10, 1904; BENBWBD AUG. 30, 1905.

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54m-vamo@ mm Pw m PATENTED OCT. 9, 1906.

T. CROSTON.

ROTARY ENGINE. APPLIGATIoN-PILED 00110, 1904. RENBWBD AUG. so, 1905.

3 SHEETS-SHIEBT 2.

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810.882,848. I PATENTBD 0813.8,1808 T. oRosToN.

ROTARY ENGINE.

APPLICATION FILED 00T. 10, 1904.l RENBWBD AUG. 30l 1905.

3 SHEETS-SHEET 3.

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THOMAS CROSTON,

oF HOQUIAM, wAsH1NeroN-"` ROTARY ENGINE.

Application filed October l0,

T0 @ZZ whom, it may concern:

Be it known that I, THOMAS CROSTON, a citizen of the United States,residing at Hoquiam, in the county of Chehalis and State of Washington,.have invented a new and useful Rotary Engine, of which the followingis-a specification.

This invention relates to that type of engines wherein a rotary pistonis employed, and the object is to provide a comparatively simplestructure having but few movable parts or elements, which parts orelements are so constructed that their cooperating portions wear so asto always maintain steam or motive-fluid tight joints, the structurebeing efficient and securing the advantages of steam expansion with theconsequent-reduction in the amount of steam necessary for operation.

The preferred embodiment 0f the invention is illustrated in theaccompanying drawings, wherein` Figure 1 is a vertical sectional viewthrough the engine. Fig. 2 isa horizontal sectional view taken on anirregular line. Fig. 3 is a view in elevation of the piston, showing thecontrolling means for the motive-Huid supply. Fig. 4 is a similar viewof said piston with the valve mechanism removed. Fig. 5 is 'a sideelevation of the valve. Fig. 6 is a view in elevation of one side of thevalve-seat is a view in elevation of the plate. Fig. 7 opposite side ofsaid plate. Fig. 8 is a vertiview therethrough, showing the calsectional packing-stirrup. Fig. 9 is a detail sectional `view throughone of the abutments, showing the valve open to permit the exhaust ofthe motive fluid. Fig. 10 is a view in elevation of one section of oneof the packing-rings. Fig. 11 is a detail sectional view showing aslightly-modified form of packing for the piston. Fig. 12 is a detailview of one end of the piston, showing the packing thereof in elevation.

Similar reference-numerals indicate corresponding parts in all thefigures of the drawm s.

Tn the embodiment illustrated a cylinder 12 is employed, carried by abase 13 and having a circular bore 14 therein, the ends of said borebeing closed by heads 15 and 16. The cylinder is Aprovided ondiametrically opposite sides with projections 17, within which areformed pockets 18, opening into the circular bore. A shaft 19, journaledSpecification of Letters Patent. 1904. Renewed August 30,

Patented Oct. 9, 1906. 1905. 'semana 276.479.

in any suitable manner, extends centrally through the bore of thecylinder and constitutes the driving-shaft of the engine. On this shaftis mounted a piston 20, the main body of which is elliptical in form, asshown in Fig. 1, the elliptical surface 21 being located betweencircular flanges 22. It will be observed by reference to Fig. 2 that thepiston terminates short of the heads 15 and 16, leaving steam-spaces 23,which are in communication between openings 24, formed in the piston.The lianges 22 fit snugly within the bore of the cylinder, and theopposite ends of the against the annular wall of provided with packingcomprising transverse strips 25, provided with cross-fingers 26, thelength of which is sufficient to bridge the pockets 18. This form ofpacking may, however, be changed, and as an example of this attention isinvited to Fig. 11, wherein a portion of a piston 20a is shown locatedwithin a cylinder 12a, the packing between the piston and cylinder beingin the form of a yielding' element 25a, secured at one edge to thepiston and located in a seat 26a, the

the bore, being outer portion being in engagement with thecylinder-wall.

Cooperating with the tory abutments 27, which are slidably mounted inthe pockets 18 between bed-plates or blocks 28, secured in the front orinner perpiston are reciprocation of the pockets, and glands 29, locatedin the rear portions of said pockets and conforming to thecross-sectional shape of the same and of the abutments, packing 30 beingarranged between the plates and glands. As illustrated in Fig. 2, thewidth of the abutments is the same as the width of the ellipticalportion of the piston, and said abutments coperate only with the same.Arranged in the pockets on opposite sides of said abutments are otherabutments 31, which bear against the peripheries of the flanges 22, thepacking 30 being extended in rear of said abutments 31 and in front ofthe glands 29. The inner ends of the abutments 27 carry foot-valves 32,that bear against the elliptical surface of the piston, said foot-valvesbeing supported on the abutments so that they may oscillate.

Motive fluid, such as steam, is introduced into one of the spaces 23through the head 15 by means of a supply-pipe 33, and this motive fluidis properly introduced intoV the IOO engine by the` following means: Thepiston is provided with an annular channel 34, having diametricallyopposite branches 35 leading therefrom and terminating indischargeopenings located contiguous to and just in rear of the ends ofthe piston, as illustrated in Fig. 1. The channel 34 is covered by acapplate 36, provided with diametrically opposite ports 37. Thecap-plate 36 is located in a recess 33, formed in the side of the pistonhaving the annular channel 34, and also located in this recess is avalve-seat plate 39, held against rotation with the piston by means ofabracket 40, that is attached to a collar 41, forming a part of theseat-plate. As illustrated in. Figs. 3, 6, and 7, the valve-seat platelhas a port 42 of considerable length, with which the ports 37 lof thecap-plate 36 are adapted to successively ,aline during the rotation ofthe piston.` This valve-seat plate, furthermore, has in one side arecessed seat 43, in which is mounted an oscillating` valve 44 in theform of a plate having a wing 45. The valve 44 is carried by a sleeve46, which is loosely journaled upon the drive-shaft 19 and is locatedwithin the collar 41 of the seatplate. To the outer end of the sleeve 46is attached a curved rack 47, with which meshes a pinion 48, carried bythe inner end of a shaft 49, journaled in and projecting from theadjacent head 15. The outer end ofthe shaft 49 carries suitable meansfor operating the same, which means in the present instance is shown inthe form of a lever 50, though any other suitable mechanismmay beemployed, if desired. It will thus be clear that by swinging the lever50 the valve 44 will be turned so as to vary the size of the port 42 ofthe valve-seat plate. in order to prevent leakage between saidseat-plate and the valve, a packing-stirrup 51 is preferably employed,seated in a slot formed in the seat- ,plate and pressed outwardly by aspring 52 against one side of the wing 45 of the valve. The outer sideof the stirrup is in the forni of I an outstanding lug 53, bearingagainst the outer edge of the wing 45 and urged thereagainst by theoutturned end of the spring 52. This structure is particularly shown inFig. 5. Other suitable packing is employed between the joints to preventleakage.

- In order to prevent the passage of steam about the peripheral flangesof the piston, packing-rings are employed, which are located in thespaces 23, and consist of sections comprising bands 55 and 56, theserings being connected by bolts 57. One of the rings is cut away andbeveled outwardly, as shown in Fig. 10. The inner side thereof bearsagainst the side of the piston. In order to prevent this side cuttinginto the piston, abutments 53 are located at suitable intervals, whichabutments also bear against the piston-face. The other ring constitutesa follower and is provided with a fiange 59,

overlying the first mentioned ring, which ring is preferably beveled, asshown in Fig. 2, and between the beveled portion and the fiange 59 islocated packing including a thin metallic band 60. lt will be evidentthat when the bolts 57 are screwed down the rings will be moved towardeach other and the packing thus forced outwardly against the annularface of the piston-bore 14. Leakage about the shaft to the exterior ofthe cylinder is prevented by suitable steam-checks or packing-boxesconsi ting of a ring 61, having a recess for packing 61a and a glandring61h, that causes the packing to press against the shaft, therebyeffecting the rotation of the boxes with the shaft. rlhe rings areconnected by bolts 61, and the outer faces of the gland-rings 61b areheld against the inner faces of the adjacent cylinder-heads or endwalls.

The means for maintaining the abutments in coaction with the piston isconstructed as follows: The head 16 of the cylinder is provided with achamber 62, and from the same lead channels 63, that have offsetdischargeorifices 64, communicating with the rear ends of the pockets18. The chamber 62 is in communication with the spaces 23, so that steamor motive fluid has free access thereto, and consequently may find itsway through the channel 63 to the pockets. This communication iscontrolled, however, by a cut-off disk 65, adjustably secured to theshaft 19 and located within the 'chamber 62, said disk havingdiametrically opposite ports 66, that move into and out of alinementwith the inlets of the channel 63 as the shaft rotates. Controlling thedischarge orifices 64 are plunger-valves 67, slidably mounted in sockets63 and movable across the orifices 64, These plunger-valves have stems69, borne against by springs 70, that urge the valves across theorifices, the tension of the springs being varied by adjusting-screws71. The exhaust from the pockets 13 is permitted through channels 72,formed longitudinally through the abutments, each terminating at one endin a rearwardly-extending orifice 73 and at the other end in an offsetorifice 73a. These exhaust channels are controlled at their inner endsby the foot-valves 32, which are provided with recesses 74, movable intoand out of alinement with the orifices 63 and channels 72 as the valvesare oscillated by the piston. This will be clear by referring to Figs. 1and 9. The outer orifices 73 are arranged to be closed when theabutments are in their outer position by block-valves 731, secured andmade adjustable by screws 73. In order to proh`bit the escape of steamaround the abutments, the same are provided at their opposite edges withpacking 75, substantially T- haped in formation, which packing extendsacross the joints between the abutments and foot-valves 32 and IOO isengaged with the latter, as indicated in Figs. l and 2. The exhaust fromth is permitted through channels 76, opening into exhaust-ports 77.

The operation of the herein-disclosed engine may be briefiy outlined asfollows: The steam or other motive fluid being admitted through thesupply-pipe 33 to the space 23 will pass into the port 42 of the valveinletplate, and when one of the ports 37 of the cap-plate of the pistonalines therewith said motive Huid will enter the channel 34, the amountso enteringand the length of time being controlled by varying the lengthof the port 42 by means of the valve 44, as will be evident. The fluidis, however, admitted just after the ends of the piston pass theabutments, which abutments will be in their outer positions, as shown inFig. 1. The steam escaping through the branches 35 will 'not onlybalance the piston, around in the direction of the arrow. While in thisposition the ports 66 of the cut-off plate 65 are alined with the inletsof the channel 63, so that the motive fiuid will find its way throughsaid channel and pressing back the plunger-,valves 67 will enter thepockets 18, thus forcing the abutments inwardly. In this position, asshown in Fig. l, the footvalves close the inlets from behind theabutments. As the piston continues its rotation the port 37 of thepiston-cap will move out of alinement with the port 42 of the valve-seatplate, and the supply of steam will therefore be cut off. Consequentlythe steam within the cylinder will expand, and this force of expansionis employed for driving the piston until the ends of the same pass theexhaustports 76, whereupon the steam confined within the cylinder willescape. Prior to this, however, and just after the cylinder hascompleted a half-revolution, so that the abutments will move outwardly,the foot-valves 32 will swing, as shown in Fig. 9, thereby bringing therecesses 74 so that the exhaustchannels 72 and orifices 73 are incommuuication. The steam confined behind the abutments willAconsequently escape, permitting said abutments to move outwardly, andthe steam finally finding a passage through the exhaust-ports 77.However, just before they abutmentsreach their outward limits ofmovement the 73 are cut off by the blocks 731), and the steam stilllocated behind the said abutments acts as cushions for the same. Priorto this, however, the cut-off disk 65 has moved so that the ports 66lare out of alinement with the channels 63, and no more steam will besupplied thereto. When this supply has ceased, the plunger-valve 67 willmove inwardly to close the orifices 64. As soon as the ends of thepiston have again passed the abutments the next port of the piston-capis brought into alinement with the port 42 of e engine I but force thesame assaGe-wa s P s the valve-seat plate and steam is again supplied toboth ends of the piston with a repetition of the action above described.

From the foregoing it is thought that the construction, operation, andmany advantages of the herein-described invention will be apparent tothose skilled in the art without further description, and it will beunderstood that various changes in the size, shape, proportion, andminor details of construction` may `be resorted to without departingfrom the spirit or sacrificing any of the advantages ofl the invention.

aving thus described my invention, what I claim as new, and desire tosecure by Letters Patent, is`

l. In a rotary engine, the combination with a cylinder havingk acircular bore, of a rotary piston located therein and comprising asubstantially elliptical body having circular fianges, movable abutmentsmounted on the cylinder and coacting with the elliptical body betweenthe flanges, said body having supply-ports that communicate and openinto the cylinder in rear of the ends of the body, and means forintermittently supplying steam simultaneously to said ports after thesame have passed the abutments.

2. In a rotary engine, the combination with a cylinder having a circularbore, of a rotary piston located therein and comprising a substantiallyelliptical body having circular flanges at its ends, movable abutmentsmounted on the cylinder and coacting with the body between the flanges,said body having an annular supply-channel, and ports leading therefromthat open into the cylinder in rear of the ends ofthe body, said portsbeing of substantially the width of the body between' the fianges, andmeans for supplying steam to the channel.

3. In a rotary engine, the combination with a cylinder having a circularbore, of a rotary piston located therein and comprising a substantiallyelliptical body having circuIar flanges at its vends that fit withinthebore, movable abutments mounted. in the cylinder and coacting with theelliptical body between the fianges, said body having an inclosedannular supply-channel provided with an inletport that opens at one sideof the piston, and valve mechanism mounted on the cylinder and having avariable supply-port into and out of alinement with which the inlet-portof the channel moves during the rotation of the piston.

4. In a rotary engine, the combination with a cylinder, of a pistonmounted therein and having wing portions, movable abutments coactingwith the piston, said piston having a motive-iiuid-supply channelprovided with branches leading to and opening in rear of thev wingportions, said channel being covered and having an inlet-port, and valvemechanism mounted on the cylinder IOO IOS

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for supplying motive fluid to the channel, said mechanism including avariable port into and out of alinement With which the inlet-port of thechannel moves during the rotation of the piston.

5. In a rotary engine, the combination. with a cylinder, of anelliptical piston rotatably mounted therein, movable abutmentscoperating with the piston, said piston having an annular fluid-supplychannel provided with outwardly-extending branches leading to points inrear of the ends of said piston, a cap-plate covering the annularchannel and having spaced ports, and means for supplyin@ motive 'fluidto the channel including a va ved port With which the ports of thecapplate successively aline.

6. In a rotary engine, the combination with a cylinder, of a pistonrotatably mounted therein and having an annular motive-'fluidsupplychannel provided with a covering having an inlet at one side of thepiston, a valveseat member mounted on the cylinder and having a portpast which the inlet of the channel-covering moves, and a cut-ofiC valvemovably mounted on the member for varying the size of the port.

7. In a rotary engine, the combination with a cylinder, of apistonrotatably mounted therein and having aI motive-fluid-supplychannel, a cap covering the channel and provided With an inlet at oneside of the piston, a stationary valve-seat mounted in the cylinder andhaving a port past Which the inlet of the channel moves, a valvecontrolling the port, and means located eXteriorly of the cylinder andconnected to the valve for moving the same.

8. In a rotary engine, the combination with a cylinder, of a pistonrotatably mounted therein and having a motive-fluid-supply channelprovided with an inlet at one side of the piston, a stationaryvalve-scat plate having a port past Which the inlet of the channelmoves, said plate furthermore having a circular seat in one side, and acut-off valve rotatably inounted on the plate and having a Wing locatedin the circular seat, said plate varying the size of the port.

9. In a rotary engine, the combination with a cylinder, of a pistonrotatably mounted therein and having a motive-fluid-supply channelprovided with an inlet at one side of the piston, a valve-seat platehaving an inletport past Which the inlet of the channel moves, a cut-offvalve cooperating with the inner side of the valve-seat plate and havinga sleeve projecting therethrough, a circular rack carried by the outerend of the sleeve, a shaft projecting through the cylinder and having apinion at its inner end that engages the rack, and means connected tothe eXterior of the shaft for operating the same.

10. In a rotary engine, the combination With a cylinder, of a shaftextending across 'rically opposite inlet-ports,

the cylinder, a piston rotatably mounted in the cylinder and having amotive-fluid-supply channel provided With an inlet-port at one side ofthe piston, said side of the piston being provided With an annularrecess, a valve-seat plate located in the recess and secured to thecylinder against rotation, said plate having a port past Which the inletof the piston-channel moves and being furthermore provided in its innerside with a circular seat, a collar carried by the valve-seat plate andsurrounding the shaft in spaced relation thereto, a sleeve rotatablymounted on the shaft and arranged Within the collar, a valve carried bythe inner end ofthe sleeve and located in the circular seat, said valvebeing movable across the port upon the movement of the sleeve, and meansconnected to the outer end of the sleeve for moving the same.

11; In a rotary engine, the combination With a cylinder, of a rotarypiston located therein, said piston having a fluid-motivesu ply channelprovided with an inlet at one si e, a valve-seat plate having a port andcooperating With the channel., said plate having a seat, a valve locatedin the seat and movable over the port to vary the siz'e of the same, anda packing-stirrup `carried by the seat-plate and having anoutwardly-springressed portion bearing against the side of the valve,and an inWardly-spring-pressed lug bearing against the edge of thevalve.

12. In a rotary engine, the combination With a cylinder, of anelliptical piston rotatably mounted therein and having an annularmotive-fluid-supply channel provided with diametrically oppositebranches leading to discharge-outlets that are located directly in rearof the ends of the piston, movable abutments cooperating With thepiston, a cap-plate carried by the piston and covering the channel, saidplate having diameta valve-seat plate secured to the cylinder and havinga port past which the ports of the cap-plate move, a valve movablymounted on the plate for varying the size of the port thereof, and meansfor moving the valve.

13. In a rotary engine, the combination With a cylinder having a pocket,of an elliptical piston mounted in the cylinder and having flanges, amovable abutment located in the pocket and bearing against the pistonbetween the flanges, and other abutments located in the pocket onopposite sides of the movable abutment and having their inner ends'bearing against the flanges.

11i. In a rotary engine, the combination with a circular bore, of anelliptical piston movable therein and having circular peripheralflanges, movable abutments mounte in the cylinder and bearing againstthe piston between the flanges, other abutments mounted in the cylinderon opposite sides of the movable abutments and bearing against IOO IOS

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the peripheries of the flanges, and packingrings bearing against theouter sides of the piston.

15. In a rotary engine, the combination with a cylinder having acircular bore and diametrically opposite pockets, of an ellipticalpiston rotatably mounted in the cylinder and having circular flanges,abutments l slidably mounted in the pockets of the cylinder and bearingagainst the piston between l the flanges, other .abutments located inthe pockets and bearing against the peripheries of the flanges, andmeans for introducing steam into the cylinder through the piston betweenthe abutments and the ends of the piston.

16. In a rotary engine, the combination With` a cylinder, of a rotarypiston located therein, a movable abutment coacting with the piston,means for introducing motive fluid into the cylinder and behind theabut# ment, means for automatically cutting off the supply of fluid tothe abutment at interf vals, and means carried by the piston forperiodically permitting the exhaust from behind the abutment.

17. In a rotary engine, the combination with a cylinder, of a rotarypiston located therein, a movable abutment coacting with the piston, amotive-Huid channel leading from the cylinder to a point in rear of thepiston, a cut-o device revoluble with the piston for cutting' oftq thechannel from the cylinder, and means separate from said revoluble deviceand controlled by the position of the )iston to permit the exhaust frombehind t e abutment.

18. In a rotary engine, the combination with a cylinder having a pocket,of a rotary piston located in the cylinder, a movable abutment mountedin the pocket and coacting with the piston, said cylinder having amotive-fluid-supply channel leading' to the rear of the pocket, ashaft-support for the piston, and a disk carried by the support andhaving ports that'aline with the channel.

19. In a rotary engine, the combination with a cylinder having aplurality of pockets and channels leading from one side of the cylinderto the rear portions ofthe pockets, of a shaft extending across thecylinder, a piston revolubly mounted in the cylinder and carried by theshaft, and a cut-oil disk mounted on the shaft and having ports that aremoved into and out of alinement with the inlets of the channels.

20. In a rotary engine, the combination with a cylinder havingdiametrically opposite pockets, a chamber in one side and channelsleading from the chamber to the rear portions of the pockets, of a shaftextending through the cylinder and chamber, a rotary piston mounted onthe shaft, slidable abutinents mounted in the pockets and coacting withthe piston, and a cut-off disk carried by the ,the space in rear of'shaft and having ports that are movableinto.,

and out of alinement with the inlets of the channels.

21. In a rotary engine,'the combination wit a cylinder, of a rotarypiston j ournaled therein, a movable abutment coacting with the piston,a motive-iiuid-supply channel leading to the rear of the abutment, and aplunger-valve located in the channel.

22. In a rotary with a cylinder, of therein, a movable the piston, amotive-fluid-supply channel leading to the rear of the abutment, and aspring-pressed plunger-valve located in the channel.

23. In a rotary engine, the combination` with a cylinder having pockets,of a rotary piston mounted in the cylinder, sliding abutments located inthe pockets and coacting with the piston, said cylinder having channelsprovided With discharge-orifices opening into the `rear portions of thepockets, plunger-valves movable across the dischargeorifices and locatedwithin the channels, springs bearing against the plunger-valves, andmeans for varying the tension of the springs.

24. In a rotary engine, the combination, with a cylinder, of a rotarypiston located therein, an abutment coacting with the piston, an exhaustfrom the cylinder, means for directing motive fluid behind the abutment,an exhaust for the motive fluid behind the abutment leading to thecylinder, and a valve for cutting off the exhaust between the cylinderand the space in rear of the abutment.

25. In a rotary engine, the combination with a cylinder, of a rotarypiston located therein, an abutment coacting with the piston, means fordirecting motive fluid behind the abutment, an exhaust for said motivefluid, said exhaust being located in the abutment, and means for closingthe channel of the abutment to prevent the exhaust therethrough.

26. In a rotary with a cylinder, of a rotatable piston located therein,a movable abutment coacting with the piston, means for directing motivefluid behind the abutment, said abutment having an exhaust-channelcommunicating with the space in rear of the abutment, and a valvecontrolling the channel and operated by the piston, said valveautomatically cutting off the abutment from the a rotary pistonjournaled nozzle. l

27. In a rotary engine, the combination with a cylinder, of a rotatablepiston located therein, a movable abutment coacting with the piston,means for directing motive fluid behind the abutment, said abutmenthaving an exhaust-channel, and a foot-valve for closing and opening thechannel between the ends of the abutment, said valve being carengine,the combination abutment coacting withy engine, the combination IOO IlO

` tions of the pockets A rthe shaft and controlling with a @yiider riedby the abutment and bearingagainst the piston.

28. In a rotary engine, the combination with a cylinr'; er, of a rotaryelliptical piston mounted therein, a sliding abutment cooperating withthe piston, means for supplying motive huid behind the abutment, saidabutment having an exhaust passage-way therethrough, and an oscillatingfoot-valve mounted on the inner end of the abutment and bearing againstthe piston, said valve controlling the exhaust.

29. In a rotary engine, the combination with a cylinder, of a rotaryelliptical piston located therein, oppositely-arranged slidingabutments, means for intermittently supplying motive fluid behind theabutments to urge the same into engagement with the piston, saidabutments being provided with longitudinally disposed exhaust channels,and oscillatory foot-valves carried by the inner ends vof the abutmentsand ,bearing against the pistons, said valves controlling theexhaust-channels of the abutments and being oscillated by the piston.

30. In a rotary engine, the combination with a cylinder havingdiametrically opposite pockets, of a shaft extending across thecylinderffan elliptical piston carried by the shaft, said piston havingan annular channel and discharge-branches opening contiguous to the endsof the piston, means for-intermittently supplying motive fluid to thechannel, reciprocatory abutments coacting with the piston andv mountedin the pockets, said cylinder'having a chamber at one end and channelsleading therefrom to the rear pora cut-off disk carried by the supply ofmotivefluid from the pockets through the channels,the abutments havinglongitudinallydisposed exhaust-channels, and oscillatory foot-valvesmounted on the inner ends of the abutments and bearing against theelliptical surface of the piston, said foot-valves controlling theexhaust-channels and being operated by the piston.

31. In a rotary engine, the combination with a cylinder having heads, ofa rotary piston located in the cylinder and terminating short of one ofthe heads, means for introducing motive-fluid supply through the headand into the space between the same and the piston, andra packing-ringarranged at the periphery of the `piston in said space and comprisingsections that are movable toward and from each other. p

32. In a rotary engine, the combination having heads, of a rotary pistonlocated'in the cylinder and terminating short of the' heads, said pistonhaving openings therethrough allowing communication between the spacesbetween the piston and vheadsfmeans for. introducing motive-fluid supplyinto one of such spaces, and packingrings located in the spaces andbearing against the sides of the piston, said rings consisting ofsections adjustably secured together and having interposed packing.

33. In a rotary engine, the combination with a cylinder, of a rotarypiston located therein, a movable abutment coacting with the piston,means for directing motive fluid behind the abutment, said abutmenthaving an exhaust-channel provided with a port, said port being movablewith the abutment, and stationary means past which the port moves forclosing and opening said port.

34. In a rotary engine, the combination with a cylinder having a pocket,of a rotary piston located in the cylinder, a reciprocatory abutmentsliding in the pocket, means directing motive ,fluid to the pocketbehind the abutment, said abutment having a longil tudinally-disposedexhaust-channel provided with an offset port in its rear endcommunicating with the rear portion of the pocket, and a valve locatedin the rear portion of the pocket and arranged to close the port whenthe abutment is moving outwardly.

35. In a rotary engine, the combination with a cylinder, of a rotarypiston located therein, an abutment coacting with the piston and havinga space in rear of the same, an exhaust from the cylinder, means fordirecting motive fluid to the space behind the abutment, an exhaust forthe motive fiuid in said space, said exhaust leading to `the cylinder,and a valve for cutting 0H the exhaust between the cylinder and thespace in rear of the abutment, said valve being automatically operatedto open the exhaustchannel when the cylinder is exhausting.

36. In a rotary engine, the combination with a cylinder, of a pistonoperating therein, an abutment-block located in the cylinder andcooperating with the piston, and a T- shaped packing for said block.

37. In a rotary engine, the combination with a piston, of anabutment-block, a swinging foot-valve carried by the block andcooperating with the piston, and a substantially T-shaped packingmounted on the abutment-block and including a bar portion connectingwith the foot-valve.

38. In a rotary engine, the combination with a cylinder having anabutment-chamber, of a rotary piston operating in the cylinder, anabutment-block located in the abutment-chamber and cooperating with theiston-bed, blocks fastened to the sides of the abutment-chamber, and agland conforming to the abutment-chamber and block and spaced from thebed-blocks, forming a packing-receiving space.

39. In a rotary engine, the combination with a casing, of a rotarypiston located therein, and a piston end packing comprising a ringhaving its peripheral portion cut out and beveled, a follower-ringcooperating IOO IIO

IIS

with said first-mentioned ring, packing nterposed between the rings,said packing being given an outward thrust by the beveled surmy own Ihave hereto affixed my signature in the presence of two witnesses.

face, and atln'n metallic band also interposed l THOMAS CROSTON' 5between the rings and being pressed thereby l Witnesses:

outwardly toward the cylinder. F. F. WILLIAMS, In testimony that l claimthe foregoing as JOHN CRosToN.

